1. Field of the Invention
The present invention relates to a recording apparatus which detects the type of recording media.
2. Description of the Related Art
Hitherto, recording apparatuses such as a printer and a printing machine which perform recording with ink on a recording medium such as a recording sheet have been widely used.
In recent years, the types of recording media have become diversified as the requirements of the market have become more diversified and the recording apparatuses have become more advanced. A variety of recording media, such as a recording sheet whose image quality has been improved by providing an ink receiving layer on the surface thereof, a paperboard such as a postcard having a thickness of at least 0.3 mm, and a piece of cloth which can be recorded on by using a printer, have been commercially used.
Typical recording apparatuses usable for the variety of such recording media are inkjet printers.
In an inkjet printer, the bleeding degree or the coloring state of ink discharged on a recording medium varies depending on the type of the recording medium. Thus, in order to achieve the best image quality, an operator sets the discharge amount and the discharge times of ink from nozzles in accordance with the type of a recording medium by instructing the printer about the type of the recording medium being used from a host computer or from instructing means of the printer.
The increased number of these instructions due to the increased types of recording media causes a complicated operation for an operator, and the printer cannot warn the operator of the wrong instruction when the operator provides a wrong instruction, thereby sometimes resulting in a recorded output having low image quality.
Also, when a network printer is shared by a plurality of operators and is not installed near some of the operators, the operators are required to go to the printer for checking what type of recording media is stored in a recording medium storage (or storage unit) before instructing the type of recording media being used, thereby causing the printer to be used inefficiently.
In a printer in which a necessary type of a recording medium can be selected from among a plurality of types of recording media, for example, by having multi-stage cassettes installed therein, an operator can realize which type of recording media is stored in which cassette only when the operator actually pulls out the cassettes, thereby causing the printer to be used inefficiently.
Some devices for detecting the type of recording media have been provided in order to overcome such disadvantages.
U.S. Pat. No. 6,151,040 has disclosed a recording apparatus and a recording method in which and by which the type of recording media is detected and recording conditions of a recording head are changed in accordance with the detected type of recording media.
Also, Japanese Patent Laid-Open No. 10-198174 has disclosed a sheet-type detector in which the type of sheets is detected by irradiating the uppermost sheet with light emitted from a light-emitting device and by detecting the reflected light by a photo receptor in order to improve its detection accuracy by setting angles of the light-emitting device and the photo receptor in the range from 15° to 30° with respect to the sheet.
In addition, Japanese Patent Laid-Open No. 71-181756 has disclosed an image forming apparatus having a recording-sheet-type detecting function in which a color sensor is disposed for detecting the type of recording sheets in each of multi-stage cassettes and, when the sensor detects the type of recording sheets, the detected information is displayed on a display unit of the apparatus. In this apparatus, when an operator operates a sheet-type selection switch at an operation unit of the apparatus so as to designate the type of recording sheets in advance to be used for making a copy of desired pages of originals consisting of a plurality of sheets, the copy is automatically made using the desired type of sheets.
However, the foregoing known examples have the following disadvantages.
In the recording apparatus disclosed in U.S. Pat. No. 6,151,040, after a starting command for printing is issued, the type of recording media is detected by recording-medium-type detecting means disposed at a point halfway through the transport route of the recording medium toward a recording section of the recording apparatus and the recording medium is subjected to recording under recording conditions in accordance with the type thereof. However, in this recording apparatus, since a printer driver in a host computer starts in reality to create printing data under certain recording conditions as soon as the starting command for printing is issued, and the data is transferred to the recording apparatus, it is difficult to change the recording conditions halfway through the transport of the recording medium.
When the recording apparatus is designed not to create recording data in a period from the issue of a starting command for printing to the completion of detecting the type of recording media, although there is no need to change the recording conditions halfway through the transport of the recording medium, the recording apparatus has a disadvantage of a prolonged recording time in total.
According to the invention set forth in Japanese Patent Laid-Open No. 10-198174, since the light-emitting device and the photo receptor are disposed in each cassette, the recording data can be created after the type of recording media in the cassette is detected in advance. However, this invention has a disadvantage that when distances of the light-emitting device and the photo receptor from the surface of the uppermost sheet change as the amount of remaining sheets varies, the amount of received light of the photo receptor varies, thereby leading to an unreliable determination about an output and resulting in wrong detection.
The invention set forth in Japanese Patent Laid-Open No. 7-181756 also has a disadvantage that since the color sensor for detecting the type of recording sheets is fixed at a specific location in the cassette, a change in a distance of the color sensor from the surface of the uppermost sheet causes wrong detection.